Siloxane-oxyalkylene block copolymers



United States "P at SILOXANE-OXYALKYLENE BLOCK COPOLYMERS Donald L.Bailey, Snyder, and Francis M. OConnor,

Kenmore, N. Y., assignors to Union Carbide Corporation, a corporation ofNew York No Drawing. Application March 22, 1954 Serial No. 417,935

15 Claims. (Cl. 260-42) tent 9 to which the name block copolymer isapplied in that I there is at least one block or section to the moleculethereof which is a silicone polymer and at least one block or sectionwhich is an organic polymer. Without regard to a particular structure orconfiguration of the molecule, the relative content of the block orblocks of silicone polymer and of the block or blocks of organic polymerpresent therein, can be illustrated as follows:

in which R and R are monovalent hydrocarbon groups and x is an integerwhich is at least one and y is an integer which is at least 3. By theterm monovalent hydrocarbon group is meant a monovalent group composedof carbon and hydrogen as for instance an aliphatic monovalent group ofwhich methyl, ethyl, vinyl, propyl, isopropyl, the butyls, the pentyls,the hexyls, are illustrative. Illustrative of monovalent hydrocarbonaromatic groups are the phenyl, the methyl phenyl and the ethyl phenylradicals and the aralkyl groups of which benzyl is representative. Thus,a silicone block of four units in which 4 the monovalent hydrocarbongroups are methyl represented by the trivalent formula MeSiO (Me SiO) E,has a molecular weight of 313 which is the minimum molecular weightattributable to the silicone block of the compositions of the presentinvention. Silicone blocks having weights as high as 50,000 can be usedbut those having a molecular weight of from 500 to 10,000 attributableto the polysiloxane chain are preferred. Furthermore, in compositionswherein the molecular weight attributable to the silicone block is morethan 327, the monovalent hydrocarbon groups need not be the samethroughout the silicone block but may differ from unit to unit or bedifferent within a single silicon unit.

Thus it is seen that in the block copolymers of this invention, thesiloxane chain contains at least one trifunctional silicon atom, that isa silicon atom bonded to a single monovalent hydrocarbon radical, andthe remainder of the chain is composed of siloxane units of the type -RSiO wherein each silicon atom is attached to two monovalent hydrocarbonradicals. For each such trifunctional silicon atom bonded to a singlemonovalent hydrocarbon radical, there isat least one and preferablythere are three polyoxyalkylene chains in the molecule.

The organic block of our compositions is a linear, predominantlyoxyalkylene polymer or chain comprised for the most part of recurringoxyalkylene groups, which groups can be represented by the generalformula (C,,H ,,O),- in which n is an integer from 2 to 4 and z is aninteger which is at least 5. Thus, a polyoxyalkylene block of five unitsin which n is 2 throughout the chain or block has a molecular weight of220 which is the minimum molecular weight attributable to the block.Organic blocks of a molecular weight up to about 10,000 can be used. Amolecular weight from about 500 to 6,000 is preferred, however. Theoxyalkylene group need not be the same throughout the organic chain orblock which can comprise oxyalkylene groups of differing molecularweights such as oxyethylene; oxy-l,2-propylene; oxy-l,3-propylene andthe oxybutylenes.

Thus, the general formula of the block copolymers of this invention isas follows:

where x is an integer and represents the number of trifunctional siliconatoms bonded to a single monovalent or multivalent hydrocarbon radical,R; a is an integer and represents the number of polyoxyalkylene chainsin the block copolymer; y is an integer having a value of at least 3 anddenotes the number of difunctional siloxane units, 11 is an integer from2 to 4 denoting the number of carbon atoms in the oxyalkylene group; andz is an integer having a value of at least 5 and denotes the length ofthe oxyalkylene chain. It will be understood further that thecompositions of matter are mixtures of such block copolymers wherein yand z are of diiferent values and that methods of determining the chainlength of the polysiloxane chains and the polyoxyalkylene chains givevalues which represent average chain lengths. In the above formula, Rand R represent monovalent hydrocarbon radicals, such as alkyl, aryl oraralkyl radicals, and R" terminates a polyoxyalkylene chain with amonoether group, R" is an alkyl radical or a radical having the formulaR Si-- where R is a monovalent hydrocarbon radical and may terminate-asiloxane chain, and

R represents a monovalent or polyvalent hydrocarbon radical, beingmonovalent when x is 1, divalent when x is 2, trivalent when x is 3,tetravalent when x is 4.

With reference to Formula I above, there is at least one oxyalkylenechain joined to a siloxane chain through a SiO-C bond, and when a=1 andx=1, there are two alkyl or R Si groups R' terminating siloxane chains.However, when a=3 and x=1, there are no such groups present.

One type of block copolymer is represented when x in Formula I is one,and in this instance a branchedchain formula may be postulated asfollows:

0 msiopwnmno) .R" (I where p+q+r=y of Formula I and has a minimum valueof 3, the other subscripts being the same as in Formula I. In thisinstance, all three of the oxyalkylene chains are joined to the end ofpolysiloxane chains of to the trifunctional silicon atom bonded only toa single.

. Patented May 13, 1958 as e ts as monovalent hydrocarbon rfdical (R').This formula may be given as follows:

R (6.32.0) .t-rnsio ),,0.=1 (R:StO) ,(cuHho) .R

(C,.H:,.O) .R" (111) (Q3 Q3 2 )z 6 Where R, r, n nd z are as d i nated.or Formula d R" a v n hyd o ar on radicai- Exp essed in -M t form theseock eopolymers may repr sented by the following torrnnla:

where p-i=q+r+s+t+n is equal to y of Formula I and in this instance hasa minimum value of 6.

The compositions of matter of this invention may be formed by reacting apolyalkoxy polysiloxane having at le st thr e k xyar h ta h t a polvilox ne cha n w t m nohydr y pe y y lky ne manethe by an xchange. eation er n t ea t part f th a ko y rouse t ached to he pelysi ox n ch n fh po yallgqxy polysiloxane are replaced by polyoxyalltylene mono-etherradicals and the allgoxy groups are removed as the correspondingalkanols. This general reaction may be r pre ente as f ll ws:

(R )(e eoaalsronta ae a-rmoouaama R"($i0.a)=(RzSiO),[(CnHylQ).R"i.(R"-")r. a-R'0H (V where R' is an alkyl radical bonded to a siliconatom through an oxygen atom and the other subscripts are as defined forFormula I.

The polyalkoxy polysiloxane which is a reactant or starting material forthe production of our block copolymen can itself be made by reacting alower molecular weight polysiloX-ane with a trialkoxysilane. Morespecifically, as described in the copending application of D. L. Bailey,Serial No. 398,225, filed December 14, 1953, a tr-imeric cyclicsiloxane, (R SiO) or a tetrameric cyolic siloxane, ('R SiO) can beeouilibratedl with a monovalent hydrocarbon-substituted trialkoxysilane,R Si(0 Alhyl) in the presence of an alkaline catalyst to produce thepolysiloxanes having alkoxy end groups as represented in siloxane may beprepared.

The monohydroxy polyoxyalkylene mono-ethers employed in the reaction toform the block copolymers must possess a definite chain-length to beelfective for the purpose of this invention, Such chain length is hereindcfined as a minimum of five oxyalkylene groups which is the chainlength found necessary to exert a significant eiiect on such propertiesas solubility and lubricity of the block copolymers. The sp ifi effectcon ribu ed y h polyoxyalkyleno chain will vary with the type ofoxyalkyh eue group ma ing up the chain. Thus pQ ysflo anepolyoxyalkyleneblock copolymers in which the oxyalkylenc groups are composed ofoxypropylene groups are waterinsoluble, whereas the molecules may bewater-soluble when the oxyalkylene group is oxyethylene, depending onthe polysiloxane-polyoxyalkylene ratio. The solubility of thepolysiloxane-polyoxyalkylene block copolymers will vary from.water-soluble. to water-insoluble. when the polyoxvalkylene chain iscompo ed of both oxyethy ne and oxypropylene groups depending on theirratio, and on the polysiloxane-polyoxyethylene ratio.

Monohydroxy polyoxypropylene monoethers suitable for the practice of theinvention are described in Fife and Roberts U. S. Patent No. 2,443,664.

Also, monohydroxy oXyethylene-oxy l,2 propylene monoethers having bothoxyethylene oxypropylenc groups in the molecule are described in Robertsand Fiic U. S. Patent No. 2,425,755. In addition, polyoxyalkylenemonoethers containing both oxyethylene and oxypropylene groups in themolecule may be formed by the sequential addition of ethylene oxide andpropylene oxide to a monohydric alcohol to form oxyalkylene chainscomposed of a sequence of oxyethylene groups followed by a sequence ofoxypropylene groups or vice versa.

The block copolymers of this invention differ from other types ofcopolymers in that the molecular weights of the polysiloxane block andof the polyoxyalkylene block can be predetermined and controlled and asthe molar ratio in which the two blocks are combined can be changed forinstance from the ratio of one siloxane block to one to nine oxyalkyleneblocks depending on the number of alkoxy groups in the polyalkoxypolysiloxane and on the number of such groups reacted, it is possible tomake block copolymers which differ widely in composition. A few of themany possible combinations are shown in the table below:

TABLE I Average molecular weights of block copolymers Molar RatioOxyalkyleue/ Polysiloxane 2 3 l 2 3 1 2 i Av. Molecular Weight of Oxyialkylene Block 500 500 500 1,001) 1,000 1,000 1,500 1,500 1.590

Av. Molecular Weight of Polysiloxane Block:

Formula above. The molecular weight of the result- It is, recognized,that when one mole of a trialkoxy ant polysiloxane is dependent upon thecharging ratios polysiloxaue is reacted with less than three moles of aemployed. The higher the proportion of cyclic trimer or tetrarner to thealkoxysi-lane, the higher the molecular weight of'the polyalkoxypolysijloxanei Thus, polyalkoxy polysi'loxanes may be formed havingmolecular weights from. about BOO-to 10,000 and upwards.

monohydroxy polyoxyalkylene monoether, the block copolymers will containalkoxy groups, and when one mole or less of the monoether is used, someof the polyalkoxy polysiloxane will be left unreacted. Such block copolymers, however, are useful in that they may be combined asse /4s withother polymers containing hydroxyl groups. For instance, by reactingthem with alkyd resins containing free hydroxyl groups, it is possibleto make silicone modified alkyd resins wherein the compatibility of thesilicone portion is increased by the attached block of oxyalkylene unitsand oxyalkylene units contribute plasticizing-properties to the alkydresin.

Where the block copolymers are not to be used as intermediates, it ispreferred that they have a low alkoxy content, and this is achieved inpractice by charging in the such as dimethyl silicone oils, are verypoor lubricantsfor such service, having practically no load-carryingcapacity. However, it has been found that the block copolymers, whosepolysiloxane content corresponds to a silicon content,of between 2% andSi by weight are excellent metal-to-metal lubricants and have betterloadcarrying capacity than the po-lyoxyalkylene fluids.

The lubricating properties of some of the block copolymers, as comparedto silicone oils, petroleum oils and polyoxyalkylene fluids, is given inthe table below:

TABLE II Oale. Viseositles, Cs. SAE Test Falex Percent ASTM Load inSeizure Slope Lbs. at 475 Test Jaw (by wt.) 100 F. 210 F. P. M Load,Lbs.

Fluid No.:

Silicone Oilspl 8. 5 29. 3 2 2502, 500 Example V 22. 7 2, 500 Example X11 86. Example VI 9. 8 49. Example IX 9. 6 74.

Reaction VI the number of moles (a) of the monohydroxy oxyalkylenemonoether equal to the number of alkoxy groups (3x) in the polyalkoxypolysiloxane. However, as illustrated in the above table, it is possibleby this method to make block copolymers which range from a low to a highpolysiloxane content.

A unique property of some of the block copolymers is theirwater-solubility, and block copolymers having that fraction of theirmolecular weight which is attributable to the oxyethylene groupsapproximately equal to or greater than those fractions which areattributable to either the polysiloxane units or to oxypropylene oroxybutylene units are water-soluble, and are at least partiallywater-soluble when the mole-fraction of oxyethylene groups is at leastone-fourth of the sum of the mole-fractions of the oxypropylene unitsand the siloxane units. The Water-soluble block copolymers are veryuseful as antifoam agents and as rubber lubricants, particularly fortire molds, Where their water-solubility permits them to be readilyapplied from an aqueous solution, and any excess lubricant to be readilyremoved from the molded article by washing. Such property of readyremoval by washing also adopts them for use as textile lubricants.

The water-soluble block copolymers are also miscible with water-solublepoiyoxyethylene-polyoxypropylene diols, monoethers and diethers and formuseful lubricants and hydraulic fluids in combination therewith. Bythemselves, or in combination with the above diols, monoethers anddiethers, or with ethylene glycol or propylene glycol, the Water-solubleblock copolymers form useful ingredicuts of lubricants having a waterbase, commonly termed hydrolubes. As the polyalkoxy polysiloxanes arethemselves water-insoluble and immiscible with the above mentionedmaterials, it is apparent that the block copolymers have greatlyenhanced utility.

Block copolymers wherein the polyoxyalkylene block contains few or nooxyethylene units are not water-soluble, but they are miscible with thestarting monohydroxy polyoxyalkylene monoethers, or the correspondingdiols or diethers, and form useful compositions in combinationtherewith.

A truly remarkable property of certain of the block copolymers is theirload-carrying capacity as metal-tometal lubricants for moving surfaces.Silicone fluids,

The identification of the fluids referred to in Table II is as follows:

The block copolymers of p'olysilo'xane blocks and polyoxyalkylene blocksthus form useful compositions over a wide range of polysiloxane content,including polysiloxane contents from 5% to by weight of the blockcopolymer. Within this range, wherein the polysiloxane content,calculated as percent silicon, is between 2% and 25%, the products areexcellent lubricants as previously stated. Within the range of 15% to50% polysiloxane, the block copolymers form useful watersoluble andsolvent-soluble fluids. And at higher polysiloxane contents between 50%and 95% the block copolymers are oils having exceptionally low pourpoints, and suitable as hydraulic fluids.

The process whereby the block copolymers may be formed has beengenerally set forth in Equation VI.

The condensation reaction depicted in Equation VI is essentially areversible reaction and is dependent upon the removal of alcoholicproducts, generally designated as R"'OH, from the reaction mixture inorder to force said reactions towards completion. .It is apparent,furthermore, that the ultimate quantity of the alcoholic product (R"'OH)removed from each reaction mixture provides an indication of the extentto which that particular condensation reaction between the polyalkoxypolysiloxane and the polyoxyalkylene glycol monoether reactants orstarting materials has reached completion.

The rate at which the alcoholic product is removed from the reactionmixture additionally serves to indicate the rate at which the reactionis progressing. That is,

7 if a large quantity of alcoholic product is removed within ashortperiod of reaction time, it may be concluded that the reactionisproceeding at a rapid rate, Whereas the reaction is proceeding at a slowrate if the amount of alcoholic product removed in the given time issmall.

The alkoxy end-blocked polysiloxanes are normally incompatible withaliphatic monoethers of polyoxyalkylene glycols and dilficulties arisein bringing about the complete reaction of the two substances. Thesedifliculties, however, are resolved by carrying out the condensationreaction in a suitable solvent, such as, for example, toluene or xylene,in which the reacting substances are mutually soluble and, thus, broughtinto intimate contact. The reaction temperature is, therefore, limitedby the reflux temperature of the polysiloxane-polyoxyalkylene glycolmonoether solution and a higher boiling solvent will permit a higherreaction temperature. Although the type of solvent is critical to thesuccess of the condensation reaction only insofar as the startingmaterials must be mutually soluble therein, it is also necessary thatthe amount of said solvent be sufficient to provide a homogeneoussolution of the starting materials at the reaction temperature, i.'e.the reflux temperature of the solution. In instances where a highmolecular weight polyoxyalkylene glycol monoether is employed as astarting material, complete compatibility despite the use of a mutualsolvent is not readily attainable. The reaction in these substancesprogresses but at a much slower rate.

Although the use of toluene and xylene as mutual solvents for thereaction mixture of this invention provide a high enough refluxtemperature to carry out the condensation reaction to completion,toluene in certain instances, is to be preferred for practical reasonsover xylene. casions the higher reflux temperature provided by a xylenesolvent encourages undesirable side reactions producing water instead ofthe expected alcoholic product. This difficulty has; been overcome bythe use of a toluene solvent which provides a lower reflux temperatureand, thus, eliminates or lessens the tendency towards bothersome side.reactions. When toluene is used as a solvent he alcoholic product,resulting from the condensation reaction is removed as an azeotrope withtoluene.

The catalysts employed in the condensation reactions described byEquation VI are, in general, the organic acids includ'i'ngtrifluoroacetic acid, perfluorobutyric acid, perfluoroglutaric acid,monochloroacetic acid, acetic acid, etc. or alkaline substances, such aspotassium silanolate, KO(SiR" C) K, wherein b is a positive integer andR" is an .alkyl radical such as methyl or ethyl, The organic acidcatalysts are active with most starting materials, and are efiective'atlow concentrations, e g, as low as 0.1 percent by Weight of the startingmaterials. They produce non-discolored, block copolymers and do notcause any degradation of the polysiloxane molecules to result inproducts which are low in silicon content as is the tendency of strongacid catalysts and alkaline catalysts. Of the organic acid catalysts,tn'fi'uoroacetic acid, perfluorohutyric acid, and perfluoroglutaric acidhave proven to, provide exceptionally high catalytic activities and,therefore, are to be preferred.

The alkaline catalysts in particular potassium silanolate containingabout 3.0 percent by weight of potassium, exhibit very high catalyticactivity. It has been found, however,. that. the use of'al'kalinecatalysts tends to cause the degradation. of the polysiloxane chainduring the condensation reaction to produce the corresponding cyclicpolysiloxancs and organo-silicone products which are low in. siliconcontent. The degradation reaction is of the reversible type. and may beopposed by means of opposing the thermodynamic equilibria of saidreaction with the addition to the initial reaction mixture of the cyclicIt has been found that on infrequent ocpolysiloxane expected to beproduced by the degradation process brought about under the influence ofthe alkalinecatalyst. For example, in preparingdimethylpolysiloxane-polyoxyalkylene glycol monoether blockcopolymerwith potassium silanolate as a catalyst the addition of appreciableamounts of the cyclic tetramer of dimethyl polysiloxane prevented anydegradation caused by the alkaline catalyst and resulted in productswhich contained the desired silicon content.

While neutral and mildly basic aqueous solutions of the water solubletypes of polysiloxane-polyoxyalkylene block copolymers of this inventionare stable against hydrolysis and remain clear and homogeneous forextremely long periods of time, strong acids and bases added to orinitially present in and unremoved from these solutions tend to attackthe readily hydrolyzable SiOC bonds present in the molecules of saidcompounds to bring about the hydrolysis of said block copolymers. Theaddition of triiluoroacctic acid, for example, to an aqueous solution ofwater soluble polysiloxane-polyoxyalkylene block copolymers caused thesesolutions to become turbid within several minutes and separate intopolyoxyalkylene glycol monoether aqueous layer and a silicone oil orpolysiloxane layer. The removal or neutralization of the acid catalystemployed in the condensation reaction, therefore, may be desirable toprovide a hydrolytically stable polysiloxane-polyoxyalkylene glycolmonoether compound.

The neutralization of the acid catalyst with stoichiometric amounts of aweak organic base, e. g. triethanol amine, monoethanolamine,monoisopropanolamine, (ll: butyl amine etc., or sodium bicarbonate,anhydrous ammonia, etc., is to be preferred over the removal of thecatalyst, as by washing with Water, and subsequent treatment withadsorption material such as silica gel or Magnesol, inasmuch as thelatter process results only in an incomplete removal of the residualacid catalyst.

The following examples will serve to illustrate the invention:

EXAMPLE I(a).BLOCK COPOLYMER FROM A TRL ALKOXY POLYSILOXANE AND A POLYOXYETHYL ENEOXYPROPYLENE MONOALKYL ETHER 108.8 pounds of mixed cyclicdimethyl polysiloxanes containing approximately 22% of the tetrarner, ofthe pentamer and 56% of higher cyclic polymers, i. e. (R SiO),, where nis at least 6; 15.6 pounds ethyltriethoxy silane and 19.5 grams ofpowdered potassium hydroxide were charged to a Pfaudler kettle having acapacity of gallons and equipped with an agitator. .The agitator wasturned on and the kettle temperature was raised to 150 C. and held therefor 3 /2 hours. At the end of this time the kettle was placed underreduced pressure and the light fractions were stripped off at anabsolute pressure of 2 inches Hg in the temperature range of 125 to 150C. About 12% to 15% of the kettle. contents were removed as lightfractions. The residue was a viscous oil having an average molecularweight of 1500 measured cryoscopically. Its ethoxy content by analysiswas 8.8 wt. percent, in good agreement with the theoretical value of 9wt. percent for a triethoxypolysiloxane of this molecular weight. Thismaterial was used to make a block copolymer as follows:

86.5 pounds (0.057 lb. moles) of monobutox-yoxyethylene-oxy-1,2,propylene monohydroxy compound containing by Weightethylene oxide units and 50% by weight propylene oxide units and havinga molecular weight of 1530, and 72 pounds of toluene were charged to thereactor and refluxed through a Dean-Stark trap until no more Water couldbe separated. 28.1: pounds (0.019 mole) of the above triethoxydimethylpolyw with total reflux at C. through the attached fractionating column. Reflux was continued with removal at trope distillingat 78 to 90 C. 2.55 pounds (0.056 mole) of ethanol were removed. At thispoint the kettle was cooled to 100 C. and 255 grams of sodiumbicarbonate was added to neutralize the acid catalyst. This quantity isabout four times that theoretically required,

'10 Physical properties of block copolymers of Examples I(a)-I(c) Theblock copolymers of Examples I(a)-l(c) hadthe following properties:

an excess being added for precaution. Reflux was re- Block copolymerestablished for 30 minutes after which the kettle contents P e t weresparged with nitrogen and the toluene stripped ofl. mp r y ExampleExample Example The product was filtered to remove residues from the bi-Ha) 1(0) carbonate neutralization after which it remained nonturbid witha yellow color. The yield was about 100 xigggg g figfygg g 95 (1) poundswhich is 90% of theory, the polymer was waterv. at210 F./V. at 100 1 "I6:255:11: 'cf'iiIII iif soluble and its viscosi y was about 880centistokes at ig figmmfgQfl-iwm 3 25 C. Elemental analysis of thisblock copolymer ASTM D-s57-52 .1 --a4. -56 i gave: Surface Tension,dyne/em 19.1 git 21.631; 19.8%.

100 F o 100 F 1 O o gea ar? 55 118736 2500., viscosity at 100 F. is 130cstks. Percent Percent 20v Gabon 535 527 Solubilities of blockcopolymers of Examples I(a)-I(c) Hydro en 9. 2. 9. 5 81110011 Theseblock copolymers had the following solubilities (Ssoluble; I--insoluble)in the following solvents:

The product was useful as a release-agent in rubber molding.

This block copolymer had the interesting property of inversewater-solubility; that is, it was soluble in water at temperatures belowabout 95 F., but not completely soluble at temperatures above this.

EXAMPLE I(b).-BLOCK COPOLYMER FROM A TRI- ALKOXY POLYSILOXANE AND APOLYPROPYLENE GLYCOL MONOALKYL ETHER Following the procedure of Example1(a), a trialkoxy polysiloxane of an average molecular weight of 800 wasprepared by substituting the following charge:

Cyclic dimethyl polysiloxanes lb 171.6 Ethyltriethoxysilane .lb 46.8Powdered potassium hydroxide grams- 31.6

A block copolymer was prepared from this triethoxy end-blockedpolydimethylsiloxane by following the procedure of Example 1(a) butsubstituting the following weights of materials:

Triethoxy polydimethylsiloxane (M. W. 800) 83.2 lb. (0.104 mole).Polypropylene glycol monobutyl ether (M. W. 714) 226.0 lb. (0.317 mole).Toluene 79.0 lb. Trifluoroacetic acid 0.9 lb. NaHCO 2.76 lb.

A water-insoluble liquid copolymer was obtained.

EXAMPLE I(c).BLOCK COPOLYMER FROM A TRI- ALKOXY POLYSILOXANE AND APOLYETHYLENE GLYCOL MONOALKYL ETHER A block copolymer was prepared fromthe triethoxy end-blocked polydimethylsiloxane of Example 1(b) byfollowing the procedure of Example 1(a) but substituting the followingweights of material:

The product was a soft solid melting at about 90 F. i

It was soluble in water at temperatures below about 192 F.

Solvents Example Example Example S I S S i S S S S S S S S I I S below65% 1 I I I S S S S S I Acetone S S S Methyl ethyl ketone S S S Butylacetate S V S S exane I ,f' S I Gasoline, I S g I Mineral spirits. Sabove S I 50% 1 Toluene S S S Carbon tetrachloride S S S MethylCellosolve. S S S Butyl Carbitol. S S S Paratfin oiL I S above I 70% 1Dlethyl silicone oil S I 1 Percent by volume of silicone in solution.

EXAMPLE II.BLOCK COPOLYMER OF A SILOXANE (M. W. 414) AND A POLYPROPYLENEGLYCOL MON 0- ETHER. (M. W. 352) weight 352), 207 grams (0.5 mole) of abranched chain ethoxy-endblocked dimethylpolysiloxane having an averageof three ethoxy groups per molecule (average molecular weight 414), 1.5grams of trifluoroacetic acid and 500 grams of toluene solvent. Thesolution was heated at the reflux temperature (115 C.) for 11.5 hoursduring which time 68.8 grams of ethanol were removed at the head of thecolumn along with a small amount of solvent. This 'was equivalent to99.7% of the theoretical amount of ethanol. The solution was then cooledand 10 grams of solid sodium bicarbonate added and the solution refluxedfor 30 minutes with stirring to neutralize the acid catalyst. Afterfiltering and removing the toluene solvent under reduced pressure therewas obtained 666 grams of a clear amber-colored oil'having a viscosityat F. of 29.3 cs. This copolymer was found to have very good lubricatingproperties and carried a load of 2250-2500 lb. on the standard Falexmachine. A polypropylene glycol monobutyl ether fluid of comparableviscosity carried 1000-1200 lb.

asserts In a two-liter flask connected to a fractionating column therewere placed 610 grams (0.174 mole) of the monobutyl ether of apolyalkylene glycol containing 50 wt. percent ethylene oxide and 50 wt.percent propylene oxide units (average molecular Weight 3500), 41.4grams (0.1 mole) of a branched chain ethoxy-endblockeddimethylpolysiloxane having an average of three ethoxy groups permolecule (average molecular weight 414), 1.3 grams trifluoroacetic acidcatalyst and 500 grams toluene 'solvent. The solution was heated at thereflux temperature (120 C.) for 3.5 hours during which time 8. grams "ofethanol were removed at the head of the column along with a small amountof solvent. This amount of ethanol was equivalent to complete reactionof the glycol monoether. The solution was thencooled and grams of solidsodium bicarbonate added and while stirring the solution was refluxedfor 30 minutes to neutralize the acid catalyst. After filtering andremoving the toluene solvent under reduced pressure there was obtained633 grams of a viscous oil having a viscosity at C. of 4,335 cs. Thiscopolymer was "found to act as an emulsifying agent for toluene-watersystems and was completely soluble in water. It represents a type ofblock copolymer having free .alkoxy groups available for furtherreaction. EXAMPLE IV.BLOC-K COPOLYMER OF A 'SILOXA-NE (M. W. 10,1921)AND A POLYPROPYLENE GLYCOL MONOETHER (M. W. 352) In a two-liter flaskconnected to a fractionating column there were placed 42.2 grams (0.12mole) of the monobutyl ether of a polypropylene glycol (averagemolecular weight 3 52), 407.7 grams (0.04 mole) of a branched chainethoxy-endblocked dimethylpolysiloxane having an average of three ethoxygroups per molecule (average molecular weight 10,192), 0.9 gram oftrifluoroacetic acid catalyst and 500 grams of toluene solvent. Thesolution was heated at the reflux temperature for 3 hours during whichtime 5.5 grams of ethanol were removed at the head of the column alongwith a small amount of solvent. This amount of ethanol was equivalent to100% reaction. The solution was then refluxed with stirring for minutesin the presence of 20 grams of solid sodium bicarbonate to neutralizethe acid catalyst. After filtration and removal of the toluene solventunder reduced pressure there were obtained 395 grams of a clear oilhaving .a viscosity at 25 C. of 163 cs. This oil was found to have anexceptionally low pour point of less than 95 F. It also had anti-foamproperties.

EXAMPLE V.--BLOCK COPOLYMEB. OF A SILOXANE (M. \V. 10,192) WITH APOLYPROPYLENE GLYCOL MONOETHER (M. W. 2230) In a two-liter flask therewere placed 334.5 grams (0.15 mole) of the monobutyl ether of apolypropylene glycol (average molecular weight 2230), 509,5 grams (0.05mole) of a branched chain ethoxy-end-blocked dimethylpolysiloxane havingan average of three ethoxy groups per molecule (average molecular weight10,192), 1.7 grams of trifluoroacetic acid catalyst and 675 grams oftoluene solvent. The solution which was nonhotnogeneous was heated atthe reflux temperature (120 C.) for 12 hours during which time 6.9 gramsof ethanol were removed at the head of the column along with a smallamount of solvent. This amount of ethanol was equivalent to 100% of thetheoretical amount. The solution was completely homogeneous at thispoint. The solution was then refluxed with stirring for 30 minutes inthe presence of solid sodium bicarbonate to neutralize the acidcatalyst. After filtering and removing the toluene solvent under reducedpressure there was obtained 780 grams of a clear viscous oil having aviscosity at 25 C. of 66,000 cs. This copolymer was completely solublein ethanol. The shear-viscosity properties were 12 comparable to those"o'f-a pure silicone oil with the added advantage of also having goodlubricating properties. The ,copolymer carried up to 2500 lb. load onthe Falex machine. This is a marked improvement over a pure silicone'oil which cannot be loaded to lb. without seizure. This copolymer wasalso found to be a good additive for polyoxylalkylene fluids. Aninteresting property of this copolymer was its emulsifying action "fortoluene water systems.

EXAMPLE VI.-BLOCK COPOLYMER FROM A TRI- ALKOXY POLYSILOXANE (M. W. 1110,AND A POLY- PROPYLENE GLYCOL MONOAIJKYL ETH'ER (M. W.625") removed atthe head of the column along with a small amount of solvent. Thesolution was then cooled and 30 grams of solid sodium bicarbonate addedand, while stirring, the solution was refluxed for 30 minutes toneutralize the acid catalyst. After filtering and removing the toluenesolvent under reduced pressure, there was obtained 1400 grams of a clearoil having a viscosity at 100 F. of 49.0 cs. This oil was found tocontain 9.8% silicon (theory was 9.9%). This copolymer was found to havevery good lubricating properties having carried a 265130111111 load onthe SAE test machine.

EXAMPLE VII.BLOCK COPOLYMER FRGM A TRI- ALKOXY POLYSILOXANE (M. W. 858)AND A POLY- PROPYLENE GLYCOL MONOALKYL ETHER (M. W1625) In a two-literflask there were placed 562.5 grams (0.9 mole) of the monobutyl ether ofa polypropylene glycol (average mol. wt. 625), 257.4 grams (0.3 mole.)of a branched chain ethoxy-end-blocked dimethylpolysiloxane having anaverage of three ethoxy groups per molecule (average mol. wt. 858), 1.2grams of trifluoroacetic acid catalyst and 450 grams of toluene solvent.The solution was heated at the reflux temperature C.) for 5 hours duringwhich time ethanol was removed at the head along with a small amount ofsolvent. The toluene solvent was removed under reduced pressure. Theresidual acid catalyst was neutralized by adding 0.9 gram oftrie'thanolamine which gave an oil having a pH of 6.75. The resultingcopolymer was a clear oil having a viscosity at 100 F. of 52.3 cs. Thisoil was found to have excellent lubricating properties having'carried2500- pound load on the standard Falex test machine. Elemental analysisof this block copolymer gave:

Found Theory wt.- 1 wt.- percent) percent) Carbon 54. 3 54. 3 Hydr n 9.5 9. 9 Silicon 8. 7 10. 7

EXAMPLE VIII.--BLOCK COPOLYMER FROM TRIALK- OXY POLYSILOXANE (M. W.1524) AND A POLYETH- YLENE GLYCOL MONOALKYL ETHER (M. W. 750) Thesolution was heated at the reflux temperature small amount of solvent.This amount of ethanol was equivalent to complete reaction. Thesolutionwas completely homogeneous at this point. The residual acidcatalyst was neutralized by stirring the refluxing solution for 30minutes in the presence of 7.0 grams of sodium bicarbonate. Afterfiltering and removing the toluene solvent under reduced pressure, therewas obtained 680 grams of a soft waxy solid whichwas a liquid at 100 F.having a viscosity of 277.5 cs. This copolymer was found to contain14.0% silicon which is in good agreement with the theoretical value of14.6%. This copolymer was soluble in water and was found to be a goodemulsifying agent.

POLYPROPYLENE GLYCOL MONOALKYL .ETHER' (AVERAGE M. W. 734) 100.0 pounds(0.136-lb. mole) of the monobutyl ether of a polypropylene gly'col(average mol. wt. 734), 39 pounds (0.045-lb. mole) of a branched chainethoxy endblocked dimethylpolysiloxane'having an average of three ethoxygroups per molecule (average mol. wt. 858), 189 grams of trifluoroaceticacid catalyst and 70 pounds of toluene solvent were charged to a reactorand heated with total reflux at 120 C. through an attached fractionatingcolumn. Reflux was continued with removal at the head of the column ofthe ethanol-toluene azeotrope distilling at 7890 C. 5.71 pounds (0.124mole) of ethanol were removed. At this point the kettle was cooled and560 grams of sodium bicarbonate were added to neutralize the acidcatalyst. Reflux was re-established for 30 minutes after which thekettle contents were cooled to 80 C. and filtered. The solution was thensparged with nitrogen and the toluene stripped ofi. There was obtained120 pounds of a non-turbid yellow oil which was 90% of theory. Thiscopolymer had a viscosity at 25 C. of 124 cs. and was found to have goodlubricating properties having carried a 320- pound load on the standardSAE test machine. The elemental analysis of the copolymer gave:

Found Theory (wt.- (wt.- percent) percent) Carbn 53. 54. 8 Hydro 9.910.0 Silico 8.9 9.6

EXAMPLE X.BLOCK COPOLYMER FROM A HEXALK- OXY POLYSILOXANE (M. W. 1686)AND A POLY- PROPYLENE GLYCOL MONOALKYL ETHER (M. W. 625) In a two-literflask connected to a fractionating column there were placed 750 grams(1.2 moles) of the monobutyl ether of polypropylene glycol (av. mol. wt.625), 337.2 grams (0.2 mole) of a multi-branched hexethoxyendblockeddimethylsiloxane oil prepared by equilibrating hexaethoxydisilylethanewith dimethylsiloxane cyclic tetramer (av. mol. wt. 1686), 1.5 gramstrifluoroacetic acid catalyst and 454 grams of toluene. The mixture washeated at reflux temperature for 7 hours during which time 58 grams ofethyl alcohol was removed from the head of the column along with a smallamount of oxygen atoms and a single monovalent hydrocarbon. radical, andjoined to at least three difunctional silicon atoms through oxysiliconbonds, each of said difunctional silicon atoms having two monovalenthydrocarbon radicals bonded thereto and the oxyalkylene polymer beingcomposed of at least five oxyalkylcne groups bonded to each other byoxycarbon bonds and bonded at one end to the siloxane polymer through acarbon-oxy-silicon bond and bonded at the other end to a monoetherradical.

2. A composition of matter as claimed in claim 1 in which the siloxanepolymer comprises from 5% to 95% by weight of the block copolymer.

3. A composition of matter as claimed in claim 1 in which the siloxanepolymer comprises from 5% to 15% by weight of the block copolymer.

4. A composition of matter as claimed in claim 1 in which the siloxanepolymer comprises from 20% to by weight of the block copolymer.

5. A composition of matter as claimed in claim 1 in .which theelementary silicon content is from 2% to 25% by weight of the copolymer.

6. A composition of matter as claimed in claim 1 in which the siloxanepolymer has an average molecular weight from about 500 to 10,000 and theoxyal'kylene polymer has an average molecular weight from about where Ris a hydrocarbon radical having the valence of x, R and R" aremonovalent hydrocarbon radicals, R is a member of the group consistingof alkyl radicals and R Si radicals, x is an integer having a value ofat least 1, y is an integer having a value of at least 3, n is aninteger having a value of 2 to 4, a is an integer having a value of atleast one and not greater than 3x and z is an integer having a value ofat least 5.

8. A composition of matter comprising a mixture of block copolymerswherein each copolymer contains a siloxane polymer and three oxyalkylenepolymers in combination and has the general formula:

wherein R, R and R" are monovalent hydrocarbon raditoluene. Aftercooling the mixture to room temperature,

0.4 gram of triethanolamine was added to neutralize the catalyst. Upondistillation of the solvent under reduced pressure, there was obtained100 grams of clear oil having a viscosity of 86.5 cs. at 100 F. Thecopolymer had excellent lubricating properties.

What is claimed is:

1. A composition of matter comprising a mixture of block copolymerswherein each copolymer contains a siloxane polymer and at least oneoxyalkylene polymer in combination, the siloxane polymer being composedof at least one trifunctional silicon atom, bonded to three integerhaving a value of 2 to 4, and z is an integer having a value of at least5. p

9. A composition of matter comprising a mixture of block copolymerswherein each copolymer contains a siloxane polymer and three oxyalkylenepolymers in combination and has the general formula:

wherein R, R and R are monovalent hydrocarbon radicals, y is an integerhaving a value of at least 6 and z is an integer having a value of atleast 5.

11. A composition of matter comprising a mixture of block copolymerswherein each copolymer contains a meters is siloxane polymer and threeoxypropylene polymers in combination and has the general formula:

wherein R, R and R" are monovalent hydrocarbon radicals, y is an integerhaving a value oi at least 6 and z is an integer having a value of atleast 5.

12. A composition of matter comprising a mixture of block copolymerswherein each copolymer contains a sil'oxane polymer and threeoxyethylene-oxyalkylene polymers in combination and has the generalformula:

wherein R, R and R" are monovalent hydrocarbon radi' cals, y is aninteger having a value of at least 6, and b and -c are integers "whosesum is at least 5.

13. A composition of matter as claimed in claim 12 in which the valuesof b,=c and y are such that the ratio is at least equal to 0. 25. t

14. A composition of matter comprising a mixture of block copolymerswherein each copolymer contains a siloxane polymer and at leastoxyalkylene polymers in combination and has the general formula:

16 wherein R is a polyvalent hydrocarbon radical having the valence of3:, TR and R" are monovalent hydrocarbon radicals, x "is an integerhaving a value of at least 2, n is an integer having a value of 2 to '4,and z is an integer having a value of at least 5.

15. A composition of matter comprising a mixture of block copolymerswherein each copolymer contains a siloxan'e polymer and six oxyalkylenepolymers in combination and has the general formula:

Klein et a1. July 19, 1949 Burkhard July 3, 1951 OTHER REFERENCESVolnov: Journal Gen. Chem. (U. S. S. R.), volume 10, 1940, pages 1600 to'1604.

UNITED STATES PATENT OFFICE CERTEFICATE OF (JORRECTION Patent No2,834,748 May 13, 1958 Donald L0 Bailey et al It is hereby certifiedthat error appears in the -printed specification of the above numberedpatent requiring correction and that the said Letters Patent should readas corrected below.

Column 9, line '70, opposite Trifluoroacetic acid" for "2.76 lba" read0,9 1b., line '71, opposite "NaHCO for "0.9 lb.," read 2076 lbs column11, line 57, for "509,5 grams" read w 509.,5 grams column 16, line 3,after "at least 2, insert y is an integer having a value of at least 3 aSigned and sealed this 19th day of April 1960 (SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Oflicer Commissioner ofPatents

1. A COMPOSITION OF MATTER COMPRISING A MIXTURE OF BLOCK COPOLYMERSWHEREIN EACH COPOLYMER CONTAINS A SILOXANE POLYMER AND AT LEAST ONEOXYALKYLENE POLYMER IN COMBINATION, THE SILOXANE POLYMER BEING COMPOSEDOF AT LEAT ONE TRIFUNCTIONAL SILICON ATOM, BONDED TO THREE OXYGEN ATOMSAND A SINGLE MONOVALENT HYDROCARBON RADICAL, AND JOINED TO AT LEASTTHREE DIFUNCTIONAL SILICON ATOMS THROUGH OXYSILICON BONDS, EACH OF SAIDDIFUNCTIONAL SILICON ATOMS HAVING TWO MONOVALENT HYDROCARBON RADICALSBONDED THERETO AND THE OXYALKYLENE POLYMER BEING COMPOSED OF AT LEASTFIVE OXYALKYLENE GROUPS BONDED TO EACH OTHER BY OXYCARBON BONDS ANDBONDED AT ONE END TO THE SILOXANE POLYMER THROUGH A CARBON-OXY-SILICONBOND AND BONDED AT THE OTHER END TO A MONOETHER RADICAL.